John is using it to mean “involves only a few variables”. I.e. if you imagine the state of the entire system has a very high dimensional vector, a constraint that only involves a few parts of the system will only involve a few dimensions of this vector.
John is using it to mean “involves only a few variables”. I.e. if you imagine the state of the entire system has a very high dimensional vector, a constraint that only involves a few parts of the system will only involve a few dimensions of this vector.